Movement stopping safety device for agricultural machine

Abstract

An agricultural machine has at least one movable tool, such as a cultivating rotor, mower or raking member, spreader disc, or other driven member such as a tractor wheel or freely rotatable roller, which parts are interrupted in movement by a protective mechanism. The mechanism can be a pawl device associated with an overload coupling in the drive train that is actuated by a mechanical or electrical monitor to overload the device. The monitor can be a pivoted cover that partly overlies a rear roller or space adjacent same with projections that intercept the roller or a trip bar with contacts that opens or closes a circuit in a system that interrupts the drive to the moving parts responsive to contact with an external object. In another variation, the circuit can have sensors such as infrared or photoelectric cells to detect the presence or lack of presence of a human operator and these sensors can be placed in a tractor cab. Alternatively, the driver seat can be in the circuit to activate the circuit when the seat is vacated.

We claim: 
     
       1. An agricultural machine comprising a rotary member that is moved during operation of said machine, a protective mechanism operatively associated with said member and positioned to prevent the movement of the same responsive to the actuation of monitor means, said monitor means being sensitive to a proximate external object to interrupt the movement of said rotary member, drive means connected to operate said machine through an overload coupling and said mechanism comprising a control device which interrupts drive to said machine upon actuation of said monitor means, said control device including a blocking member and the actuation of said monitor means causing said blocking member to retard the movement of a rotary shaft of said drive means whereby said overload coupling disengages the drive to the machine. 
     
     
       2. An agricultural machine as claimed in claim 1, in which the said mechanism comprises an electric switch which is actuated by the monitor means to energize the control device by completing a circuit. 
     
     
       3. An agricultural machine as claimed in claim 1, in which said blocking member includes a rod which cooperates with a pawl wheel mounted on said shaft, said rod being displaced upon actuation to interrupt the rotation of said shaft. 
     
     
       4. An agricultural machine as claimed in claim 1, in which the protective mechanism comprises an electrically insulated member which is movable by the object to close a switch and complete a circuit that energizes the device. 
     
     
       5. An agricultural machine as claimed in claim 4, which the machine comprises a hay-making machine and said insulated member surrounds the rotary member. 
     
     
       6. An agricultural machine as claimed in claim 1, in which said machine is a centrifugal fertilizer dispenser having an ejection member, the latter being surrounded by a protective monitor. 
     
     
       7. An agricultural machine comprising a roller member that is moved during operation of said machine, a pivotable cover at least partly overlying said member and positioned to prevent the movement of the same responsive to the downward actuation of cover, said machine having rotatable cultivating members positioned in advance of said roller with respect to the normal direction of operative travel, a space between said cultivating members and said roller, said cover bridging the space and means biasing the cover to an inoperative rest position. 
     
     
       8. An agricultural machine as claimed in claim 7, in which said cover has depending projections that arrest the rotation of said roller. 
     
     
       9. An agricultural machine as claimed in claim 8, in which said cover is pivotable about an axis extending transverse to the direction of travel and spring means resists the downward movement of said cover from a rest position of the cover.